Miniaturized Circular Patch MIMO Antenna with a Defected Ground Structure for Localization Systems

This paper presents an ultra-wideband MIMO antenna with low mutual coupling that is useful in real-time location systems. The frequency range in which this antenna is simulated is 3.1 to 10.6 GHz. The antenna is designed as a circular monopole patch modified by incorporating a square cut in the center, with a rectangle attached to it, followed by adding an elliptical shape to form a circular head with rectangular stepped notches within the lowered ground plane to improve impedance matching and bandwidth. A defected ground structure (DGS) is used to reduce mutual coupling between the MIMO antenna elements, and high isolation of S11 < −20 dB can be achieved without increasing the spatial gap. The compact design also integrates parasitic elements to further improve isolation and minimize interference. The antenna demonstrates stable radiation characteristics, moderate gain, and excellent diversity performance throughout the UWB frequency band. Due to its compact size, broadband, and enhanced isolation, the proposed MIMO antenna is an efficient and practical solution for RTLS applications. Its reliability of performance can make it suitable for modern communication systems.